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This site is neither a next “Photography school” nor “Professional manual”. This is just a set of my own tests and graphics, which I have developed while trying to better understand photography principles. I hope that some of them would be useful for visitors of my website also. If you look for professional advices and/or such sources of information, I would recommend jumping to “my favorite links” at the bottom of this page. Equations & Principles |
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Thin Lens Optics - Equations Basic equations derived for thin lenses. Relations between focal length, magnification factor, object and image distances. Angle of view as a function of focal length. |
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Spherical & Parabolic mirrors focusing Drawings demonstrating: - spherical aberration. - perfect focusing in parabolic mirror. |
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Spherical lens - aberrations Drawings demonstrating: - spherical aberration. - chromatic aberration. |
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Magnifying glass Drawings demonstrating: - construction principles. - relations between object & image. - magnification. |
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Microscope Drawings demonstrating: - construction principles. - relations between object & image. - magnification. |
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Optical telescope Drawings demonstrating: - construction principles. - relations between object & image. - magnification. |
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Measurements |
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FF-BF - focus test chart Simple test allowing to check if the lens is affected by Front Focus or Back Focus. Print the test chart. Place it in front of your camera assuring 45° angle between chart and lens axis. In order to assure high accuracy tripod should be used. Point AF to the middle of the red cross and shoot the picture. Read from the taken picture real focusing point. |
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Field of View test charts The set of four test charts allowing fast and easy FoV measurements. Available formats: - 3x2 & 4x3. - A4 & A3. |
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Angle of View & Focal Length measurements Simple method allowing measurement of the angle of view and calculating focal length of the lens. Follow instructions included in the file. All you need is: two rulers and the tripod. |
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Lens' tests |
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EF 24-105mm f/4L IS USM versus EF 28-135 mm f/3.5-5.6 IS USM Resolution & Distortion tests at: - minimum focal length. - minimum distance. |
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EF 24-105mm f/4L IS USM versus EF 28-135 mm f/3.5-5.6 IS USM Resolution & Distortion tests at: - maximum focal length (F=105/109 mm chosen to assure the same magnification for both lenses). - 1 m distance. |
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Noise measurement There are several sources of the noise in digital cameras, however most of the noise has a random nature. Random images are hard to compress, so the length of the compressed file (e.g. JPG) can be used as a measure of the noise level. More noise on the picture causes heavier files. This is true as long as we can assure that no other image is recorded on the sensor. Below are presented results of such estimations. The tests have been conducted with gray scale and the lens with the cap placed on it. In order to allow comparison of two different cameras some data was normalized to 10 Mpx sensor. Conclusions are very interesting and sometimes surprising. |
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EOS 5D Mark II & III noise comparison Native ISO speed for both cameras is 160. Only multiples of ISO 160 allow to achieve the lowest noise level for dark scenarios. |
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EOS 5D Mark II noise test Native ISO speed for this camera is 160. Only multiples of ISO 160 allow to achieve the lowest noise level for dark scenarios. Exposures above 4 seconds cause rapid growth of the noise level. |
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PS-G10 noise test Extremely low noise for ISO 80 and ISO 100. Exposures above 1 second cause rapid growth of the noise level. ISO 1600 for exposures above 1/8 second cause not acceptable level of the noise. |
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PS-G10 noise test - EV Estimation of the noise level for overexposed and underexposed images. Surprisingly ISO 1600 produces noisy pictures even if properly exposed. |
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EOS 5D Mark III noise reduction system test Tests for noise reduction system set to low & high position. Visualization of the noise for various ISO speeds. |
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EOS 5D Mark II & III noise squares - comparison Visualization of the noise for various ISO speeds. |
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EOS 5D Mark III noise squares Visualization of the noise for various ISO speeds. |
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EOS 5D Mark II noise squares Visualization of the noise for various ISO speeds. |
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PS-G10 noise squares Visualization of the noise for various ISO speeds. |
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PS-G10 noise squares Visualization of the noise for various ISO speeds and various exposures. |
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PS-G10 Random Noise squares (at 4 seconds and ISO 200) Visualization of random nature of the noise. Ten shots at the same condition given different patterns. |
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PS-G10 Static Noise Removal Dynamic visualization of static & random nature of the noise (based on PS-G10). Extended exposure time causes increase of random noise density. Double exposure techniques applied above 1 second removes static noise (see red arrows). |
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Excel Calculators Please note that equations commonly used for lenses are accurate only for thin and single lenses. In many cases additional assumption is made that the distance to an object is long enough. All of below calculators are presented only for educational purpose. |
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Angle of view versus focal length Calculations and graphs. |
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Cropping versus focal length Lenses with focal length above 400 mm are very expensive, so most of amateurs used to crop their pictures. Calculator allows to estimate the focal length which should be used instead of cropping. |
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Hyperfocal distance Calculations and graphs. |
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Depth of Field Calculations and graphs. |
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Extension tubes Estimation of magnification factor and light loss caused by extension tubes. |
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Distance & Object Size relations Calculations: - distance to the object based on its size. - object size based on the distance to object. |
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Maximum object speed without image blurring Estimation of values: - maximum speed of an object without image blurring. - maximum speed of the camera (shift). - maximum lens rotation during exposure time. |
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Speed, exposure & aperture Collection of various ISO scales used in the past. Presentation of relations between exposure & aperture. |
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Various |
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Canon Lenses - Angle of View - comparison Drawing of Angle of View for major Canon lenses - PDF file. |
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Canon Lenses & Extension Tubes - Angle of View - comparison Drawing of Angle of View for major Canon lenses with Extension Tubes - PDF file. |
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Jokes |
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Canon for left handed people My own design - so far not available, even in the best stores near you. :-) |
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Links |
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Links to photography websites Collection of the best websites related to photography. Covered subjects: - Photography schools. - Math & Optics for photographers. - Equipment tests & reviews. - History of Photography. - Technology. - Forums. - Photo Galleries. |
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